LEEDS, England — Leeds has backed calls for the introduction of temporary concussion substitutions after one of its players played on following a clash of heads after passing on-field tests, only to be withdrawn 15 minutes later having developed symptoms.

Robin Koch sustained a blow to the head in a challenge with Manchester United midfielder Scott McTominay during a Premier League game on Sunday, but was cleared to continue — with his head bandaged — following a lengthy delay while he took concussion tests.

Koch was taken off shortly after, supported by two of Leeds’ medical staff.

Leeds manager Marcelo Bielsa said after the match that Koch was substituted because of the effects of a cut in his head, not because he had concussion symptoms. The club, though, said in a statement on Monday that the Germany defender had suffered a concussion and would now be following return-to-play protocols.

“The medical staff at Leeds United have always been in favor of temporary substitutions for head injuries,” Leeds said, “as it would allow the staff more time to assess an injury and allow a period for symptoms to potentially develop.”

Since last year, teams have been able to make a permanent concussion substitution following a head injury. That allows them to retain their three regulation substitutions.

Football Association guidelines state that players who sustain a suspected concussion “should immediately be removed from the pitch and not allowed to return until the appropriate treatment has been administered.”

Before Leeds’ update on Koch, the Professional Footballers’ Association had said Monday that the “if in doubt, sit them out” protocol was not being applied consistently in the sport and that the current concussion protocols weren’t prioritizing player safety.

The PFA said it has pushed for the introduction of temporary concussion substitutes because it would allow medical teams more time to assess a player’s condition.

“Introducing temporary substitutes would allow a match to restart with neither side numerically disadvantaged, reducing pressure on players and medical teams to make quick decisions on whether an injured player continues,” the PFA said.